112811-90-2

112811-91-3

112006-57-2

Example 5 Synthesis of N,N-dimethyl-2-(phenylmethylthio)-3-pyridinecarboxamide: A mixture of 29.7 parts of thionyl chloride, 50.0 parts of 2-(phenylmethylthio)-3-pyridinecarboxylic acid, and 225 parts of ethyl acetate was heated and refluxed for 1.6 hours. Upon completion of the reaction, the resulting 2-(phenylmethylthio)-3-pyridine carbonyl chloride solution was cooled to 5°C. While maintaining the temperature at about 10°C, 70 parts of a 40% aqueous solution of dimethylamine were slowly added. The reaction mixture was adjusted to pH 4.0 with a 36% hydrochloric acid solution, followed by decantation to separate the lower aqueous layer. Water was added to the remaining ethyl acetate layer and the mixture was distilled to completely remove the ethyl acetate. After cooling, crystallization was induced by inoculation and N,N-dimethyl-2-(phenylmethylthio)-3-pyridinecarboxamide was collected by filtration, washed with water and dried. A final product of 52.1 parts was obtained in 93.9% yield with a melting point of 61°-63°C.